This invention relates to a bead-forming machine, and particularly to a bead-forming machine capable of forming annular beads in relatively thick-walled steel tubing, e.g. twelve gauge or sixteen gage steel tubing.
Commercial bead-forming machines are marketed by various companies, additional companies are using bead-forming machines of various types to produce enhanced value tubing products. In most cases the bead-forming machinery is used with thin-walled tubing that is relatively deformable, e.g. copper or aluminum.
The present invention is concerned with a bead-forming machine capable of forming a bead (or flare) in a relatively thick-walled tubing, e.g. steel tubing having a relatively thick wall. The invention is usable with twelve gauge or sixteen gauge steel tubing.
In one preferred embodiment of the invention, the machine comprises an internal circular die (roller) adapted to engage the inner surface of a tubular work piece, and an external circular die (roller) adapted to engage the outer surface of the tubular work piece. The work piece material between the two dies is subjected to a squeezing (extrusion) force as the material passes through the restricted space provided by the mandrels.
The extrusion action of the dies produces an ironing action on the work piece material, such that irregularities and wrinkles are effectively removed from the bead formed by the mandrels. During the bead-forming operation the work piece material is subjected to bending forces and also extrusion forces. The combination of forces produces a uniform cross section bead in a relatively thick-walled steel tubing work piece.
Further features of the invention will be apparent from the attached drawing and description of a preferred embodiment of the invention.